7480 datasheet(261/337 Pages) RENESAS

261 / 337 page

7480 Group and 7481 Group User's Manual

2-46

APPLICATIONS

2.10 Differences between 7480 and 7481 Group, and 7477 and 7478 Group

The 7480 Group and 7481 Group have almost the same functions as the 7477 Group and 7478 Group.

However, take the following differences into consideration when using the former to replace the latter.

2.10.1 Functions Added to 7480 Group and 7481 Group

Table 2.10.1 lists the functions added to the 7480 Group and 7481 Group.

Table 2.10.1 Functions added to the 7480 Group and 7481 Group

2.10 Differences between 7480 and 7481 Group, and 7477 and 7478 Group

Added Function

Bus Arbitration

STP and WIT Instruction

Watchdog Timer

Built-in Clamping Diode

Description

• In serial I/O communication of the bus-contention system, the

level of the TxD pin is compared with that of the RxD pin.

When there is a mismatch, a bus arbitration interrupt is generated

to detect bus collision.

• The valid/invalid of the STP and WIT instructions is selectable

by writing 2 times to the STP instruction operation control register.

• Watchdog timer returns program to the reset state if a runaway

occurs.

• Each pin of ports P4 and P5 has a built-in clamping diode, by

which voltages VCC or more can be applied.

Note: In the 7480 Group, port P5 is not implemented.

7480 Datasheet(PDF) 261 Page - Renesas Technology Corp